Light-sensitive diazonium compounds and diazotype materials

ABSTRACT

DIAZOTYPE MATERIAL OF INCREASED LIGHT-SENSITIVITY AND RATE OF DYE IMAGE DEVELOPMENT IS OBTAINED WITH AN ORTHOACYLAMINO - META - HALO-PARA-AMINO BENZENE DIAZONIUM COMPOUND. ONE-COMPONENT MATERIAL CAPABLE OF RAPID NEUTRAL DEVELOPMENT MAY BE PREPARED, AS WELL AS TWOCOMPONENT MATERIAL WHEN UTILIZING COUPLERS OF LOWER ACTIVITY.

United States Patent 3,736,143 LIGHT-SENSITIVE DIAZONIUM COMPOUNDS ANDDIAZOTYPE MATERIALS Hans-Dieter Fromrneld, Wiesbaden-Biebrich, SiegfriedScheler, Wiesbaden-Schierstein, and Arno Brauninger, Wiesbaden-Biebrich,Germany, assignors to Keufiel & Esser Company, Morristown, N .J.

No Drawing. Filed Dec. 14, 1970, Ser. No. 98,061 Claims priority,application Germany, Dec. 17, 1969, P 19 63 252.1 Int. Cl. G03c 1/54U.S. Cl. 96-91 R 2 Claims ABSTRACT OF THE DISCLOSURE Diazotype materialof increased light-sensitivity and rate of dye image development isobtained with an orthoacylamino meta halo-para-amino benzene diazoniumcompound. One-component material capable of rapid neutral developmentmay :be prepared, as Well as twocomponent material when utilizingcouplers of lower activity.

BACKGROUND OF THE INVENTION Benzene diazonium compounds carrying atertiary amino group in 4-position to the diazonium group have been usedas light-sensitive substances in the diazotype field for a relativelylong time. These compounds may contain further substituents in thebenzene ring, preferably in the 2- and 5 or 2- and 3-positions to thediazonium group, e.g. acylamino groups, alkoxy groups or halogen atoms.The properties of the said compounds which make them suitable for thediazotype field are substantially determined by the said substituents.

It is also known that, for the production of one-component diazotypematerials, rapidly coupling diazonium compounds are preferably used,since only then the dyestuif formation during development occurs at areasonable speed. If the dyestuif formation occurs too slowly, thewater-soluble diazonium compound diliuses during development from thenon-exposed into the exposed portions of the reproduction material.Undersirable blurred lines are then obtained.

Diazonium compounds for one-component diazotype materials are repeatedlydescribed in the literature. Dutch published patent application No.6,610,037 discloses compounds carrying a halogen atom in the 2- and3-positions to the diazonium group, British patent specification No.1,082,889 discloses compounds carrying an acylamino group in 2-positionto the diazonium group and an alkoxy radical in 3-position. The couplingspeed of all these compounds is not sufiicient for the presentrequirements, since one-component diazotype materials have increasinglybeen preferred which can be developed with weakly acid developers. Thesame applies to compounds carrying an alkylmercapto group in Z-positionand a halogen atom in 3-position to the diazonium group.

French patent specification No. 93,482 discloses compounds carrying anacylamino group in 2-position and a phenoxy radical in 5-position. Thesecompounds couple somewhat more rapidly, but their coupling speed is notentirely satisfactory in an acid medium. Furthermore, they have thedisadvantage that they generally form azo dyestutr's which have arelatively poor absorption in the ultraviolet range of the spectrum.

A still higher coupling speed is exhibited by the compounds carrying anacylamino group in 2-position to the diazonium group and an alkoxy groupin 5-position and in which, contrary to the above compounds, the4-position is occupied by a thioether or acylamino radical ICC ratherthan a tertiary amino group (British patent specifications Nos.1,064,129, and 1,045,242; U.S. patent application Ser. No. 883,302 andGerman published patent application No. 1,256,065). These compounds havethe disadvantage, however, that they are relatively insensitive tolight.

SUMMARY OF THE INVENTION The present invention provides benzenediazonium compounds deriving from the unilaterally diazotizedpphenylenediamine, which are characterized by the general formula:

R{\ /R2 N R4- Ra Ra RflOn 0C N NzX wherein R and R are alkyl, aralkyl orcycloalkyl radicals or,

together with the nitrogen atom, a heterocyclic radical;

R and R, are hydrogen or halogen, one of which is hydrogen;

R and R are alkyl, aralkyl, cycloalkyl or aryl radicals;

n stands for 0 or 1; and

X is an anion.

The diazonium compounds of the invention are distinguished from theknown compounds by an increased coupling speed, good light-sensitivityand stability.

The compounds of the invention preferably are used in one-componentdiazotype material. This material has a satisfactory light-sensitivityand can be developed with alkaline as well as with weakly acid buttereddeveloper solutions. The advantage of the high coupling speed of thediazonium compounds of the invention, of course, plays an important partin development in a neutral or weakly acid medium since at such a pHvalue development generally is performed more slowly.

In combination with very slowly coupling azo components, e.g. 7' hydroxy1,2,4,5 naphthimidazole or 2-hydroxy 8 biguanidino-naphthalene, thecompounds of the invention may also be used in two-component diazotypematerials which are developed by ammonia vapor or by heating.

DESCRIPTION OF THE INVENTION In the compounds of the invention, R and Rmay be alkyl, aralkyl or cycloalkyl radicals which may be unsaturatedor, in known manner, carry further substituents, e.g. halogen, hydroxyor amino groups. Preferably used are alkyl groups of 1 to 4 carbonatoms, aralkyl groups of 7 to 10 carbon atoms and clycloalkyl groups of5 to 7 carbon atoms. If R and R together with the tertiary nitrogenatom, form a heterocyclic radical, this radical may derive, eg frompyrrolidine, piperidine, piperazine, N-methylpiperazine, Nacylpiperazine, thiomorpholine, morpholine, hexamethyleneimine, and thelike, and again be substituted. The mode of action of these radicals isknown in the diazotype field.

For economical reasons and because of the easy accessibility, thepreferably selected halogen atom R or R is is chlorine. But also othercompounds may be used in which R or R is bromine, fluorine or iodine.

In the compounds of the invention the acylated secondary amino groupincludes the acyl radical COO -R which may derive from an aliphatic oraromatic carboxylic acid (11:0) as well as from a carbonic acidsemiester (11:1), an urethane grouping resulting with the aminonitrogenatom.

R and R may be alkyl, aralkyl, cycloalkyl, and aryl radicals. Preferablyused are alkyl groups with 1 to 7, aralkyl groups with 7 to 10, andcycloalkyl groups with 5 to 7 carbon atoms. The radicals R and R mayalso be substituted. Preferred substituents are alkoxy groups, halogenatoms or substituted amino groups.

X is one of the anions usual in the diazotype field, which form stablediazonium salts. The diazonium salt may be present, [for example, as achloride, sulphate, tetrafluoroborate, hexafluorophosphate or as adouble salt with zinc chloride, tin tetrachloride, cadmium chloride, andthe like.

Examples of the benzene diazonium compounds of the invention are:

( 1 2-(N-methyl-N-acetyl-amino) -3-chloro-4-dimethylamino-benzenediazonium hydrogen sulphate (melting point 121 C.)

(2) 2- N-methyl-N-ethoxycarbonyl-amino -3-chloro-4-dimethylamino-benzene diazonium hydrogen sulphate (melting point 75C.)

(3 2- N-propyl-N-ethoxycarbonyl-amino -4-dimethylamino-S-chloro-benzenediazonium chloride, tin tetrachloride double salt (melting point 82 C.)

(4)2-N-propyl-Nbenzyloxycarbonyl-amino)-4-dimethylarnino-S-chloro-benzenediazonium tetrafluorobor ate (oil) (5 2- (N-cyclohexyl-N-acetyl-amino-4-dimethylamino- S-chloro-benzene diazonium tetrafiuoroborate (meltingpoint 138 C.)

(6) 2- (N-cyclohexylacetylamino)-3-chloro-4- dimethylamino-benzenediazonium chloride, zinc chloride double salt (melting point 88 C.)

(7) 2- (N-cyclohexyl-N-ethoxycarbonyl-amino)-4-dimethylamino-S-chloro-benzene diazonium tetrafluoroborate (meltingpoint 83 C.)

(8) 2- (N-n-butyl-N-acetyl-amino -4-dimethylamino- S-chloro-benzenediazonium tetrafluoroborate oil) (9) 2-(N-benzyl-N-acetyl-amino)-4-dimethylamino5- chloro-benzene diazoniumchloride, tin tetrachloride double salt (melting point 83 C.)

(10) 2-(N-benzyl-N-acetyl-amino)-3-chloro-4-dimethylamino-benzenediazonium tetrafluoroborate (melting point 114 C.)

( 1 1) 2- (N-benzyl-N-ethoxycarbonyl-amino-4-dimethylarnino-S-chloro-benzene diazonium tetrafluoroborate (meltingpoint 69 C.)

( 12) 2- (N-benzyl-N-ethoxycarb onyl-amino -3-chloro-4-dimethylamino-benzene diazonium tetrafluoroborate (melting point 93C.)

( 13) 2- [N- j3-phenyl-ethyl-N-ethoxycarbonylamino]-4-dimethylamino-5-chloro-benzene diazoniumchloride, zinc chloride double salt (melting point 91 to 92 C.)

( 14) 2- N-methyl-N-ethoxycarbonyl-amino -4- (N- methyl-N-n-butylamino)-5-chloro-benzene diazonium tetrafiuoroborate 15) 2-(N-methyl-N-acetyl-amino) -4- N-methyl-N-cycloheXyl-arnino)-5-chloro-benzene diazonium chloride, Zinc chloridedouble salt (melting point 120 to 121 C.)

( 16) 2- N-rnethyl-N-ethoxycarbonyl-amino) -4- (N- methyl-N- cyclohexyl-amino -5-chlorobenzene diazonium tetrafiuoroborate (oil) 17 2-(N-methyl-N-acetyl-amino) -4- (N-methylbenzyl-amino) -5-chloro-benzenediazonium chloride, zinc chloride double salt (oil) (18)2-(N-cyclohexyl-N-acetyl-amino)-4-diethylamino-S-chloro-benzenediazonium tetrafluoroborate (melting point 112 to 113 C.)

( 19) 2- (N-cyclohexyl-N-chloroacetyl-amino)-4-diethylamino-S-chloro-benzene diazonium tetrafluoroborate (meltingpoint 93 to C.)

(20) 2-(N-cyclohexyl-N-ethoxycarbonyl-amino)-4-diethylamino-S-chloro-benzene diazonium tetrafluoroborate (melting pointto 106 C.)

(21 2- (N-benzyl-N-ethoxycarbonyl-amino) -3-chloro-4-diethylaminobenzene diazonium tetrafluoroborate (melting point76 to 78 C.)

(22) 2-(N-methyl-N-acetyl-amino)-4-pyrrolidino-5- chloro-benzenediazonium chloride, tin tetrachloride double salt (melting point 140 to142 C.)

(23 2- (N-cyclohexyl-N-acetyl-amino) -4-pyrrolidino- S-chloro-benzenediazonium chloride, zinc chloride double salt (melting point 167 C.)

(24)2-(N-cyclohexyl-N-ethoxycarbonyl-amino)-4-pyrrolidino-5-chloro-benzenediazonium chloride, zinc chloride double salt (melting point 128 C.)

(25 2- (N-benzyl-N-ethoxycarbonyl-amino) -4-pyrrolidino-S-chloro-benzenediazonium chloride, tin tetrachloride double salt (melting point 114 C.)

(26 2- N-methyl-N-acetyl-amino) -4-piperidino-5 chloro-benzene diazoniumtetrafluoroborate (melting point 130 to 131 C.)

(27) 2-(N-methyl-N-ethoxycarbonyl-amino)-4-piperidino-S-chloro-benzenediazonium chloride, tin tetrachloride double salt (melting point 71 to72 C.)

(28 2- (N-propyl-N-acetyl-amino) -4-pi=peridino-5- chloro-benzenediazonium chloride, tin tetrachloride double salt (29) 2 [N(,B-diethylamino-ethyl)N-acetyl-amino]-4- piperidino-S-chloro-benzenediazonium hexafluorophosphate hexafiuorophosphoric acid (30) 2 [N (6piperidino-ethyl)-N-aoetyl-arnino]-4- piperidino-S-chloro-benzenediazonium hexafluorophosphate hexafluorophosphoric acid (31) 2 (N methylN acetyl-amino)-4-(4'-methylpiperidino) 5 chloro-benzene diazoniumtetrafluor borate (melting point 129 to 130 C.)

(32) 2 (N-methyl-N-acetyl-amino)-4- (3-methyl-piperidino)-5-ch1oro-benzene diazonium chloride, tin tetrachloride doublesalt (33) 2 (Nmethyl-N-ethoxycarbonyl-amino)-4-heptamethyleneimino-S-chloro-benzenediazonium hydrogen sulphate (melting point 95 to 96 C.)

(34) 2 (N methyl N-acetyl-amino)-4-morpholino-5- chloro-benzenediazonium hydrogen sulphate (melting point 126 to 128 C.) V 1 (35) 2(N-methyl-N-acetyl-amino) 4- morpholino-S- bromo-benzene diazoniumchloride, Zinc chloride double salt (melting point to 127 C.) (36) 2 (Nmethyl-N-benzoyl-amino)-4 morpho1ino-5- chloro-benzene diazoniumchloride, zinc chloride, sodium chloride salt (melting point 122 to 125C.)

(37) 2 (N-methyl-N-ethoxycarbonyl-amino)-4 morpho- 1ino-5-chloro-benzenediazonium hydrogen sulphate (melting point 99 to 100 C.)

(38) 2 [N ('y-methoxy-propyl)-N-benzyloxycarbonylamino]-4-morpholino-5-chloro-benzene diazonium chloride, tin tetrachloridedouble salt (39) 2 (N-cyclohexyl-N-acetyl-amino)-4-morpholino-5-chloro-benzene diazonium hydrogen sulphate (melting point 185 C.)

(40) 2(N-cyclohexyl-N-ethoxycarbonyl-amino)-4-morpholino-S-chloro-benzenediazonium chloride, tin tetrachloride double salt (melting point 181 C.)

(41) 2 (N-benzyl-N-acetyl-amino) 4 morpholino-S- chloro-benzenediazonium chloride, zinc chloride double salt (melting point 132 C.)

(42) 2 (N-benzyl-N-ethoxycarbonyl-amino)-4-morpholino-5-chloro-benzenediazonium tetrafiuoroborate (melting point 138 C.)

(43) 2 [N (4' methoxy-phenyl)-N-acetyl-amino]-4-morpholino-S-chloro-benzene diazonium chloride, tin tetrachloride doublesalt (melting point 170 to 171 C.)

(44) 2 (N methyl-N-acetyl-amino)-4-(3'-methyl-morpholino) 5chloro-benzene diazonium hydrogen sulphate (melting point 198 to 200 C.)

(45) 2 -(N methyl-N-acetyl-amino) -4-(3,5-dimethylmorpholino) 5chloro-benzene diazonium hydrogen sulphate (melting point 131 to 134 C.)

(46) 2 (N methyl-N-acetyl-amino)-4-(N-methyl-piperazino)-5-chloro-benzene diazonium chloride, zinc chloridedouble salt (melting point 178 to 180 C.)

The melting points'referred to above are of the corresponding nitrocompounds which are reduced and diazotized to form the indicateddiazonium compounds.

For the preparation of the diazonium compounds of the invention,2,5-dichloro-aniline is acetylated, nitrated and deacetylated.2,5-dichloro-4nitro-aniline is then alkylated, e.g. methylated. By thereaction with a primary amine, e.g. butyl amine, 2chloro-4-nitro-5-buty1amino-N,N-dimethyl-aniline is obtained, which isthen acylated, reduced and diazotized.

According to a second method of synthesis, the starting material is3,4-dichloro-aniline, which is acetylated, nitrated and deacetylated.3,4-dichloro-6-nitro-aniline is reacted, for example, with morpholineand, via a subsequent Sandmeyer reaction, 2,5-dichloro 4morpholinonitrobenzene is obtained. The reaction with'y-methoxypropylamino, for example, yields2-nitro-4-chloro-5-morpholino-N-y-methoxy-propyl) aniline which isreacted with chloroformic acid ethyl ester and then reduced anddiazotized.

The base of the diazotype material produced with the compounds of theinvention may be opaque, such as paper, linen, coated papers andmetallic materials or translucent, such as coated and uncoated tracingpapers or transparent, such as for example cellulose acetate, polyesteror polycarbonate films. When the surface of the base is hydrophobic asin the case of plastic films, the diazonium compound preferably isincorporated together with the usual additives into a hydrophilic filmlayer which has been applied to the surface of the hydrophobic base.

An excellent djazotype material is obtained with the use of atransparent base, e.g. natural transparent paper, transparentized paper,tracing cloth or polyester film, which carries on the surface ahydrophilic film layer,

which has been produced by superficial hydrolysis of a lacquer layerfrom cellulose ester or polyvinyl ester.

When the base is transparent or at least translucent, particularly thediazotype material produced therewith is very suitable for theproduction of intermediate originals.

In addition to the diazonium compound of the invention and, possibly, acoupling compound, the light-sensitive layer of the diazotype materialmay contain the usual additives, e.g. acids, such as citric acid,tartaric acid, boric acid, sulph'osalicylic acid, stabilizers, such asnaphthalene- 1,3,6-trisulphonic acid and its water-soluble salts,antioxidants, such as thiourea, metal salts, such as aluminum sulphate,binders, such as gelatin, gum arabic and synthetic resin as well assilica dispersions.

PREFERRED EMBODIMENTS.

Example 1 White photoprinting base paper is provided with a precoat offinely divided silica and polyvinyl acetate and then coated with asolution of 0.5 g. of citric acid 3.5 g. of the sodium salt ofnaphthalene-1,3,6-trisulphonic acid, and

1.7 g. of 2-(N-methylN-acetyl-amino)-4-(N-methyl-N-cyclohexyl-amino)-5-chloro-beneznediazonium chloride, zinc chloride double salt (No. 15)

in ml. of water and dried.

After imagewise exposure to light, development is carried out with thefollowing solution;

0.33 g. of phloroglucin 9.6 g. of trisodium citrate 2.4 g. of sodiumbenzoate 0.2 g. of adipic acid 2.0 g. of sodium adipate 5.7 g. of sodiumchloride 0.2 g. of the sodium salt of a dialkyl naphthalene sulphonicacid as the wetting agent in 100 ml. of Water.

The pH value of the solution is about 6.

The copies have strong brown-violet lines which become visibleimmediately upon the application of the developer liquid.

Example 2 Natural transparent paper is coated with a solution of:

0.5 g. of citric acid 3.0 g. of the sodium salt ofnaphthalene-1,3,6-trisulphonic acid 0.02 g. of saponin, and

3.4 g. of 2-(N-methyl-N-acetyl-amino)-4-(4'-methylpiperidino) 5chlorobenzene diazonium tetrafluoroborate (No. 31)

30 ml. of water and 20 ml. of isopropanol and dried.

The material is exposed to light under an opaque line drawing and thelatent image is developed according to the so-called thin-layer methodby applying the following solution:

0.06 g. of phloroglucin 0.4 g. of resorcin 1.5 g. of sodium benzoate 5.0g. of trisodium citrate 1.0 g. of sodium formate 1.0 g. of thiourea 0.1g. of the sodium salt of an alkyl naphthalene sulphonic acid as thewetting agent in 100 ml. of water.

The pH value is about 7.0.

7 Immediately upon the application of the developer, the developed imageis visible in dark brown lines wh1ch absorb ultraviolet light very well.The copy obtained is thus excellently suitable as an intermediateoriginal for making further copies. Similarly good results are obtainedwith the compounds Nos. 5, 8, 44 and 45.

Example 3 Transparent paper is lacquered with acetyl cellulose and thelacquer layer is superficially hydrolyzed up to a depth of about 3.5After the removal of the chemicals used for hydrolysis by washing withwater, the hydrophilic surface is sensitized with the followingsolution:

0.5 g. of citric acid 4.0 g. of the sodium salt ofnaphthalene-1,3,6-trisulphonic acid 0.1 g. of saponin, and

4.0 g. of 2-(N-benzyl-N-ethoxycarbonyl-amino)-3-chloro-4-dimethyl-amino-benzene diazonium tetrafluoroborate 85 ml. of water and15 ml. of isopropanol.

The material is exposed to light under an original and developed withthe solution indicated in Example 1. The copy obtained has violet lineson a transparent background and is very suitable as an intermediateoriginal. Similarly good results are obtained with the compounds Nos.26, 34 and 37.

Example 4 White photoprinting base paper is provided with a precoat ofrice starch and polyvinyl acetate and then sensitized with a solutionof:

0.5 g. of citric acid 4.0 g. of the sodium salt ofnaphthalene-1,3,6-trisulphonic acid, and I 2.0 g. of2-(N-cyclohexyl-N-acetyl-amino)-3-chloro-4-dimethylamino-benzenediazonium chloride, zinc chloride double salt (No. 6)

in 100 ml. of water.

When the diazotype material thus obtained is imagewise exposed to lightand developed with the developer described in Example -1, copies withbroken-violet lines on a white background are obtained. 1

For the determination of the development speed, an unexposed strip isdeveloped according to the so-called thinlayer method in agrooved-roller machine with the developer of Example 1 and, immediatelyupon leaving the machine, cut into three parts. Further development isstopped on Part I 15 seconds, and on Part II 30 seconds after theapplication of the developer by exposure to a strong light source,whereas Part III, for achieving the maximum color density, is passed asecond time through the developing machine. In the case of thismaterial, after 15 seconds 89% and after 30 seconds 96% of the maximumdensity are achieved.

When a material containing, instead of theindicated diazonium compound,an equimolar quantity of the double salt of2,3-dichloro-4-dimethylamino-benzene diazonium chloride and zincchloride is treated in the same manner with the same developer, after 15seconds 57% and after 30 seconds 76% of the maximum color density areachieved. When using 2-ethylmercapto-3-chloro-4-dimethylamino-benzenediazonium tetrafluoroborate instead of the indicated diazonium compound,the corresponding values are 38% after 15 seconds and 55%. after 30seconds, when using 2-(N-cyclohexyl-N-acetylamino)-3-methoxy-4-dimethylamindbenzene diazonium tetrafluoro-borate, thecorresponding values are 56 ,after 15 seconds and 74% after 30 seconds.

8 Example 5 White photoprinting base paper is coated with a solution of:

0.5 g. of tartaric acid 3.5 g. of the sodium salt ofnaphthalene-l,3,6-trisulphonic acid, and

2.2 g. of 2-(N-cyclohexyl-N-ethoxycarbonyl-amino)-4-pyrrolidino-5-chloro-benzene diazonium chloride, zinc chloride doublesalt (NO. 24)

in m1. of water and dried.

After imagewise exposure to light, the material is developed with asolution of:

0.6 g. of phloroglucin 0.6 g. of resorcin 1.5 g. of thiourea 7.2 g. ofpotassium tetraborate 0.8 g. of potassium hydroxide 0.1 g. of the sodiumsalt of isopropyl naphthalene sulphonic acid in 100 ml. of water.

The pH value of this liquid is about 9.5.

Copies with red-brown lines are obtained. Similarly good results areobtained when using the compounds Nos. 13, 14, 18 and 23.

Example 6 White photoprinting base paper is provided with a precoat fromrice starch and polyvinyl acetate and then coated with a solution of 0.3g. of gum arabic 0.5 g. of citric acid 0.02 g. of saponin, and

1.76 g. of 2-(N-cyclohexyl-N-ethoxycarbonyl-amino)-4- dimethylamino 5chloro-benzene diazonium tetrafluoroborate (No. 7)

in 100 ml. of Water and dried (Material A). i

By exposure to light under an original and development with a solutionof:

0.4 g. of phloroglucin 0.1. g. of acetoacetanilide 0.25 g. of benzoicacid 1.5 g. of sodium benzoate 15.0 g. of sodium formate, and

0.1 g. of the sodium salt of the mono-(Z-ethyl-hexyl) ester of sulphuricacid in 100 ml. of water, which has a pH value of about 5.8, copies withstrong violet lines are obtained.

If the developing speed is determined as described in Example 4, after 5seconds 87% and after 10 seconds 91% of the maximum density areachieved.

If the diazonium compound of the invention is replaced by an equimolarquantity of 2-(N-cyclohexyl)- N-ethoxycarbonyl-amino)-4-dimethylamino-5-(4 chlo ro-phenoxy)-benzene diazonium hydrogen sulphate described inFrench Pat. 93,482 (Material B), the corresponding values are 76% after5 seconds and 86% after 10 seconds. Material A of this example upondevelopment thus needs half the time for achieving 87% of the maximumdensity than Material B.

Transparent paper lacquered with acetyl cellu'ose is superficiallyhydrolyzed to a depth of about 3.0, and the hydrophilic surface thusobtained is coated with a solution of:

0.5 g. of citric acid 0.1 g. of saponin, and

3.5 g. of 2-(N-cyclohexyl-N-ethoxycarbonyl-amino)-4-dimethylamino-5-chloro-benzene diazonium tetrafluoroborate (No. 7)

ml. of isopropanol, and 90 ml. of water and dried (Material A1).

Upon exposure to light under an original and development with the abovedeveloper, a transparent copy with dark violet lines is obtained whichis excellently suitable as an intermediate original for making furthercopies because the dyestuff has a good absorption for actinic light.

For comparison purposes the same base was coated with a solutioncontaining an equimolar quantity of the above-noted prior compound(Material B1). By exposure to light and development with the samedeveloper, copies with blue-black lines are obtained, which have a muchpoorer absorption for actinic light.

As compared with the fully exposed background of the copy, the imageareas of the copy obtained with Material A1 have a transmission of 6.5%at 405 nm. Under the same conditions the image areas of the copyobtained with Material B1 have a transmission of 13.0%.

What is claimed is:

1. A light-sensitive diazonium compound of the general formula:

wherein R is methyl or ethyl, and

R is alkyl of 1-4 carbon atoms, cyclohexyl, or benzyl; or

R and R together with the nitrogen atom form a piperidine, piperazine,pyrrolidine, morpholine, or

heptamethyleneimino;

R and R are hydrogen, chlorine, or bromine, one of which is hydrogen,the other being halogen;

R is alkyl of 1-7 carbon atoms, aralkyl of 7-10 carbon atoms,cyclohexyl, or (B-piperidino)-ethyl;

R is acetyl, ethoxy carbonyl, chloroacetyl, benzyloxycarbonyl, orbenzoyl; and

X is an anion.

2. Diazotype material comprising a support having a coating thereon of acomposition consisting essentially of a light-sensitive diazoniumcompound according to claim 1.

References Cited UNITED STATES PATENTS 3,520,692 7/1970 Knoester et al96- 91 R 3,416,925 12/1968 Sus et al. 96-91 R 3,547,637 12/1970 Scheleret al 96-75 X 3,261,684 7/1960 Wilders et al 96-49 3,311,475 3/1967 VanLoon et al 96-91 R 3,338,713 8/1967 Hendrickx et a1. 96-91 R 3,028,2404/1962 Werner et a1. 96-91 R 3,463,639 8/1969 Baltazzi 96-91 R 3,560,2152/1971 Knoester et a1. 96-91 R 2,980,534 4/1961 Printy et a1. 96-49 X3,497,355 2/1970 Mizianty 96-91 R 3,615,578 10/1971 Hectors et al 96-91R FOREIGN PATENTS 1,534,978 6/1968 France 96-91 R OTHER REFERENCESDinaburg, M. S., Photosensitive Diazo Compounds, The Focal Press, 1964,pp. -62 and 71.

Kosar, 1., Light-Sensitive Systems, J. Wiley & Sons, 1965, pp. -196197.

CHARLES L. BOWERS, JR., Primary Examiner US. Cl. X.R.

